These reactors are used both for exothermic as well as endothermic reactions. In the first case, the plate heat exchanger functions to remove heat from the reactor container. In the second case, the plate heat exchanger is used to supply heat. The catalysts used are generally in the form of pourable catalyst particles that are held in the space or spaces between the individual heat-exchanger plates of the plate heat exchanger. This not only creates one or more reaction spaces but in fact heat transfer spaces are also defined by the heat-exchanger plates and the heat transfer medium is conducted through these spaces.
Reactors of this type are generally well-known and have proven successful, and reference is made in this regard to DE 1 97 54 1 85. The specific catalyst through which the reactive medium flows is in the space(s) between the adjacent heat-exchanger plates and creates a fixed bed. The heat-exchanger plates are thermal plates through which a cooling medium flows. They are formed by at least two sheet-steel plates joined at predetermined points so as to create flow channels. The plate heat exchanger is installed on a perforated base whose mesh size is designed to be smaller than the particle size of the catalyst particles.
Whenever the catalyst or catalyst particles in these reactors are exhausted, they need to be replaced. This is also true whenever the catalyst particles have been poisoned or otherwise consumed. This typically necessitates a procedure whereby the reactor must be completely or partially dismantled.
For this reason EP 1 234 612 has provided an alternative where a thin layer of the catalyst is applied to at least one part of the overall surface of the heat-exchanger plates or thermal plates. This primarily prevents the individual catalyst particles from being able adhere during the time the reactor is used as intended since they can only be removed from the reactor with considerable effort. This procedure furthermore prevents catalyst grains or catalyst particles from getting wedged in the individual thermal plates. In extreme cases, this can even result in the creation of recesses in which no catalyst particles are present. This is of course unacceptable for the uniform, nonhazardous, and efficient operation of the process during conversion of the reactive medium.
The desired goal in any case for the procedure disclosed in EP 1 234 612 is to be able to increase the overall useful cooling or heating surface area per reaction space volume, the values indicated in this case for the lower limit being 150 m2/m3. The above-described problems when the catalyst is used, its possible poisoning and in particular regarding replacement of the catalyst have not been solved by these actions.
The same applies with the generic reactor set forth in EP 2 045 006 A1. The reactor here is provided with flat extended spacers that are heat-exchanger plates between two thermal plates. The goal of the spacers is to enable improved cleaning of the heat-exchanger plates. Another intended purpose of the spacers is to enhance strength. This is relevant, in particular, whenever the operation uses individual thermal plates consisting of plate packets. The approach of the known teaching also uses an extensive spacer designed as a closed box whose interior is equipped with devices to record reaction parameters. These may involve, for example, sensors or also nozzles for performing the cleaning function. Also described is a design for the extensive spacers in the form of catalyst cages. What remains unchanged, however, is the fact that the actual spacers are between the two thermal plates or join them to each other. Any replacement of the catalyst thus turns out to be just as difficult as before.
A reactor that has heat-exchanger plates is described in DE 100 31 347 that functions in the conventional manner with a catalyst packing between individual heat-exchanger plates. Special emptying devices are provided here to allow catalyst to be discharged as required.
Finally, U.S. Pat. No. 3,528,783 should also be referenced that relates to a catalyst reactor using a sandwich design. Here a heat exchanger plate is typically coated with the catalyst material, after which another heat exchanger plate is mounted. Problems of catalyst replacement do not come into play here. This is where the invention intends to provide a complete solution.